In FY2019, the Pathology Core served 85 users from 49 Laboratories/ PIs and have more 280 histopathology requests. The numbers of Core user and Laboratory/PI are steadily growing. In addition to NHLBI laboratories, we have services for 20 laboratories and PIs from 8 Non-NHLBI users. We made 21,820 histology slides, including about 7,196 frozen slides. Among these, we have made 2,927 routine H&E stained slides and more than 747 special staining slides, includes Masson trichrome, PAS, elastic and Oil-red O staining. We also performed about 535 immunohistochemstry slides with either peroxidase-DAB or fluorescence labeling. We have added to our repertoire of procedures based on suggestions by users of ways to optimize their research. The key factor for the Core is adaptability on response to users needs. a) The Core offers consultation in human and non-human cardiac and pulmonary pathology. b) We provide working bench training for Core users. c) Core collaborates with PI to develop new techniques. d) We have solicited feedback from the Steering Committee and potential users to better understand their needs. The pathology Core has contributed 4 publications in FY2019. Our Core not only provides service for NHLBI DIR laboratories, we are also open to NIH campus wide for their histology needs. For FY2019, we have users from 8 different institutes other than NHLBI, who sent requests to us because of customer services, quality, convenience and low costs.